1. Field of the Invention
The present invention relates to an optical waveguide which enables light to be used for positioning both a light-emitting device and a light-receiving device, and to an optical wiring member including the optical waveguide. Furthermore, the invention relates to a method of mounting optical devices on an optical wiring member.
2. Description of Related Art
In electronic devices, such as communication devices, information processing devices, household electrical appliances, and the like, optical signals are sometimes used to transmit information within an electronic device or between an electronic device and an outside device. In comparison with the electrical signal, the optical signal is advantageous in terms of transmitting a large capacity of information (fast communication rate), having no influence of electromagnetic noise, and the like.
To transmit optical signals, an electronic device is equipped with an optical wiring member. The optical wiring member includes a substrate and an optical waveguide comprising an optical waveguide core disposed on the substrate and an optical waveguide clad which entirely covers the optical waveguide core (hereafter, also simply referred to as “optical waveguide”). When an optical wiring member is mounted on an electronic device, a light-emitting device (LD; laser diode) and a light-receiving device (PD; photodiode) are mounted on the surface of the substrate on which the optical waveguide is not disposed. On the optical waveguide core, a mirror is formed at a location that faces the light-emitting device and at a location that faces the light-receiving device, thereby optical signals emitted from the light-emitting device reach the light-receiving device via the optical waveguide (see, e.g., JP-A 2007-17559).
As described above, on a substrate, there is a location at which a light-emitting device is mounted and there is a location at which a light-receiving device is mounted, and before mounting the light-emitting device and the light-receiving device (collectively referred to as “optical devices”), those mounting locations must be properly positioned. Conventionally, there is a position-aligning method which has the advantage of the property that an optical waveguide core allows light to efficiently pass through. In this method, when light, such as illuminating light, is emitted on one end of the optical waveguide core, i.e., a location at which an optical device is mounted, the light exits from the other end of the optical waveguide core, i.e., a location at which the other optical device is mounted, and therefore, optical devices are positioned using the light as a target.
However, in this conventional method, once an optical device is mounted to one end of the optical waveguide core described, e.g., in JP-A 2007-17559, illuminating light can no longer be introduced into the optical waveguide core from that location; therefore, it is impossible for the light to exit from the other end and serve as a target for positioning the other optical device. This means that light can be used only for positioning either a light-emitting device or a light-receiving device.